If the sphincter allows any leakage from the stomach, some of this acid might move back into the esophagus, causing 1. Heartburn
2. Saliva
3. Constipation
4. Diarrhea

the water is warmed up by the sun and then it evaporates into the atmosphere. the sunlight warms the water by its heat. water is then cooled down and condensation takes place. the water then finally returns back to the earth by the process of precipitation in the form of rain or ice.

explanation:

the answer u all are looking for is 4000000000000000000000 million years.